Disabling a mailing machine when a print head is not installed

Abstract

Mailing machine including a controller, a printer module including a connector, a print head controller for producing print data signals necessary to print a postal indicia on an envelope and a replaceable print head cartridge having a plurality of print elements which are selectively energizable in response to the print data signals. The print head cartridge is detachably mounted to the connector. The controller in operative communication with the printer module for: determining if a valid print head cartridge is installed; and if a valid print head cartridge is not installed, preventing the print data signals from reaching the connector.

What is claimed is:  
     
       1. A method of operating a mailing machine including a printer module and an accounting module in operative communication with the printer module, the printer module including a print head controller for producing print data signals necessary to print a postal indicia on an envelope and a replaceable print head cartridge having a plurality of print elements which are selectively energized in response to the print data signals, the accounting module in operative communication with the printer module for producing a token necessary to generate the print data signals, the method comprising the following step(s): 
       determining if a valid print head cartridge is installed; and  
       if a valid print head cartridge is not installed, disabling the accounting module for producing the token.  
     
     
       2. The method of claim  1 , further comprising the following step(s): 
       disabling the print head controller from producing the print data signals.  
     
     
       3. The method of claim  2 , wherein the mailing machine further includes: 
       a transport means for feeding the envelope past the plurality of print elements; and  
       encoder means operatively coupled to the transport means for providing encoder signals indicative of the position of the envelope, the encoder means, the transport means and the print head controller for synchronizing the feeding of the envelope with energizing of the plurality of print elements of the print head module; and  
       further comprising the following step(s):  
       disabling the encoder means from producing the encoder signals.  
     
     
       4. The method of claim  3 , wherein the mailing machine further includes: 
       a motor operatively connected to the transport means; and  
       a motor controller operatively connected to the motor for transmitting suitable drive signals to the motor; and  
       further comprising the following step(s):  
       if the valid print head cartridge is not installed, disabling the motor controller from transmitting drive signals.